Having done my second track day yesterday at Japfest (just got through the sound check at 99db) I have a problem with my car overheating after the first lap it rose to 111 end of second 117 then 120 I did try a higher gear to lower the revs and increase the air flow but it didn\'t work and landed up \'nursing\' the car around Castle Coombe yesterday although I still enjoyed camp corner and quarry The car did the same at Odiham and the other RX7 owner said that with his V Mount it never got above 85 so is this the only answer I still wish to keep the air con so can this be the answer because it never overheats on the road i.e. up to 95 then cools.
Not really David, it will be something silly like sluge in the coolant, one fan not working, thermostat not fully opening. So make sure all those things are ok first, and the airways are free from debris.
The normal coolant system for a fairly stock set up is man enough for a track day.
I thought I checked all that and its only recently had a rebuild rad water is clean and blue checked both fans come on. I have thought for a long time that the massive front mounted IC stops any flow of air to the rad which is also behind the A/C rad too
The only thing you could try is to improve the ducting.
Otherwise V mount is the only way forward.
Quote from: David Wiltshire;693732I thought I checked all that and its only recently had a rebuild rad water is clean and blue checked both fans come on. I have thought for a long time that the massive front mounted IC stops any flow of air to the rad which is also behind the A/C rad too
Sorry david I did not realise that you had a fmic, I had a good look at my system the other day and I have to say that now the a/c rad is getting older the fins are not as open now what with corrosion and road dirt. So maybe time to ditch the a/c ?
I\'m still of the opinion that the main radiator does not get any air flow I have been toying with the idea of altering the undertray to form a long low scoop that would not effect ground clearance too much but just provide a flow of air where at the moment it seems obvious there\'s not, it may be just the case that a V-Mount will be a cure all having had a look with an inspection mirror the A/C fins are clear and good.
David,
In comparison, I was round Castle Combe at Japfest, and whilst I didn\'t check my water temp on the first lap, I noted that my air temp was around 50 deg C, due to heat soak waiting to go on track. So I backed off for the first lap to get tyres and brakes warmed and a good air flow thru\' the front mount. Water temp and air temp on the second lap were showing \'normal\' for my car at 80 deg C water and 25 deg C air. Similar temps were shown for the last lap.
This is using a Koyo rad, large front mount and a custom front undertray which is flat without vents. Although my front spoiler/nose has large inlets for the intercooler and oil coolers.
Hope this helps.
Chris
I think my first move will be to get an upgraded radiator. I was on the track about 2.30 and I don\'t think the ambient temperature was that much higher than when I saw you on track. When I did the Odiham trackday it was about the same ambient temperature so its definately the car, plus I\'ve read you have to dump the A/C with a V-Mount which is not an acceptable option for me. I know Castle Coombe is known for its very limited run off before hitting something solid but I do like it as a track. I also made a point of not running the engine whilst waiting to go on track because I had this nagging feeling about the car potentially running hot. I have to say this is twice I\'ve recorded 120 in the car and engine wise seems to be fine at the moment, I did of course wait till it had cooled then checked the water level and all was well.
Hi David,
Sorry to hear you couldn\'t get the best out of your car yesterday ,
Don\'t know what mods you have under the bonnet as this will dictate the cooling system, if your stock with stock intercooler, twin turbo\'s etc you can use the Koyo rad as a direct replacement keeping your air con in the same place,
Hope this helps
Yes its all fairly stock a very big FMIC (G-Reddy) still twins, water injection and of course the air con rad with a 99 spec front end. Does it make any difference it being a late 97 model 40000+ because I\'ve seen mostly 92-95 models covered.
FMIC is generally the culprit to overheating.
well, I can tell you now that you can keep your AC with a V-Mount set up! it just meand a little fiddleing! I opted to bin mine due to the system not actualy working, but if you are going to make a custom V-mount using the Greddy cooler & koyo rad (if you opt for one?) then you just have to allow for the AC rad!
I\'ve done my V-Mount and pumped up the power to about 330 running 0.9 bar boost and I struggle to get the coolant up to temp! on the motorway coming up & going back I was sat at a steady 79c and I saw 80c on the way home for about 10 mins! likewise, intake temps didn\'t cross 20c all the way! my set up is using a stock rad & Blitz cooler with stainless water & cooler pipes!
Jono
Quote from: Jono FD3;693886well, I can tell you now that you can keep your AC with a V-Mount set up! it just meand a little fiddleing! I opted to bin mine due to the system not actualy working, but if you are going to make a custom V-mount using the Greddy cooler & koyo rad (if you opt for one?) then you just have to allow for the AC rad!
I\'ve done my V-Mount and pumped up the power to about 330 running 0.9 bar boost and I struggle to get the coolant up to temp! on the motorway coming up & going back I was sat at a steady 79c and I saw 80c on the way home for about 10 mins! likewise, intake temps didn\'t cross 20c all the way! my set up is using a stock rad & Blitz cooler with stainless water & cooler pipes!
Jono
I think you have the answer there that I\'m looking for, one of my friends owns a large engineering business so I am sure I can get him to make the V-Mount frame does anyone have any drawings? I have just noticed another post about a radiator issue on this forum and there is a question about the AST is this a potential problem that also needs to be looked at?
Quote from: David Wiltshire;693798Yes its all fairly stock a very big FMIC (G-Reddy) still twins, water injection and of course the air con rad with a 99 spec front end. Does it make any difference it being a late 97 model 40000+ because I\'ve seen mostly 92-95 models covered.
If your on an old stock silted up rad , there\'s your problem,
Greddy front mount should pass more than enough air to feed a koyo rad and keep it all cool, I say this because its your easiest way forward.
Does the original radiator have a green painted top? If so then you do have a point although the rad water is a clean as the day it was put in. It would be nice to think that the rad replacement would solve it the only problem is that its only on track when it happens not on the roads and to replicate track speeds on the road would be a tad risky to say the least.
I\'ve had a look around and found a Koyo for £440 is that about what you have to pay? Alternatively there is one on e-bay for about £169 now I know you get what you pay for in life, but is there anywhere doing the genuine article cheaper?
Question - have you got your stock undertray still fitted?
Yes, although I was tempted to cut and form a scoop underneath
hmm I do know when I didnt have an undertray fitted my water temps went up, refitted a tray and water temps have gone down. I have a massive FMIC , uprated rad but no aircon rad.
Try replacing your thermostat with a lower temp rating version
Your right, I think I\'ll pop down and see Geff or Chris because I have checked the obvious like the fins/airflow with an inspection mirror so maybe the rad is suspect or just not up to the job.
My money\'s on teh stock rad - my first thought was undertray too, but if it\'s still tehre, won\'t be that - for god\'s sake don\'t chop it - you\'ll probably only make matters worse. The stock undertray helps massively with keeping the car cool by creating a low pressure zone in the bay,
fwiw i\'ve a re-worx v-mount with aircon still working and it is really good for temps, geff will sort you out!
Hi Dave, I have a Blitz FMIC and a Koyo rad, removed air con rad.and homemade undertray as per Clives advice a good few years back!Along with this I have the Apexi to \'force \' fans on at 95degs. I still have heat probs but only if after a good thrash and then to idle but fans soon sort this.
PM me as per my profile and pop round to Horndean and check my set up. car on jacks at the mo.
Paul
Thanks Paul, I popped down to see Geff at RE-Worx and as ashc said they can retain the air-con as I want. Max had exactly the same problem with his racing RX7 and its a constant 85 now so as expensive as it may be I\'m of the opinion that you do these things once and do it properly. So when I have the money to do it I\'ll have a G-Reddy FMIC for sale.
They have an 185F degree Fan Switch. This will turn the fans on much sooner then the stock unit. Pettit Racing sells one as do others.
Few things to help the rx7 cooling. Turn the fans on sooner, easily done with a different thermoswitch, and easily done with a PFC and datalogit. Make sure the undertray is in place. Seal all gaps next to and around the radiator. Insure the fans are coming on. Upgrade to a fluidyne, koyo, mishimoto and etc aluminum radiator. Vented hood. And burb the cooling system properly. It\'s very difficult to get the air out of the system, so work it out as best you can, and continue to check it several days after filling it. Check pressure cap should be 13- 16 psi and working properly.
Those temps are way too high, should never continue running laps at those levels. Turn the heater on and get it down below 100c. I don\'t boost my car if the temps are above 93c